🦠microbiology review

Chromogen

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

A chromogen is a substance that can be converted into a colored compound, often used in immunoassays to indicate the presence of specific antigens or antibodies. In laboratory analysis, chromogens are key components for visualizing results in assays like EIAs and ELISAs.

5 Must Know Facts For Your Next Test

  1. Chromogens are essential for producing visible signals in enzyme-linked immunosorbent assays (ELISAs).
  2. The color change from chromogens is typically measured using a spectrophotometer.
  3. Common enzymes linked with chromogens in EIAs include horseradish peroxidase (HRP) and alkaline phosphatase (AP).
  4. The intensity of the color produced by a chromogen correlates with the concentration of the target molecule.
  5. Chromogenic substrates must be carefully selected to ensure they produce a clear, measurable color change.

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